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Maybe. The only reason my finches were diagonsed with it was because I had a new-bird quarentine and vet exame and fecale done. They weren't showing any signs of disease, both had good wieghts and were active, if a little on the old side, so it appears that an animal can have it for a long time without becoming ill. I'm betting your snake was infected at a previous owner or even petstore or breeder.
I have to say I will never use ivermectin on ... the ivermectin treatment. I never gave her the second injection.

Sorry to hear about your snake, that sounds really bad. I think Ivermectin is what my vet used to treat the pentastomid infection.

Followup. I asked her, and she didn't use Ivermectin. She used Praziquantel.

Initial indications are that it worked - there have been no signs of parasites since the second dose, but I'll be getting a faecal in a week or two to check for sure. In the meantime, since this would appear to be a zoonose, any interaction with the snake or its vivarium involves disposable surgical gloves.